When removing a very heavy load (e.g. an off-shore platform) from a floating barge to place it on a non-floating support (e.g. another floating support or a structure standing on the sea bed), there is a critical period when the load is no longer completely supported by the floating support. This period continues until the load and the floating support are completely separated. During the critical period the floating support tends to drop away from the load during troughs in the swell and then to collide with the load when the swell rises to a crest. Therefore, to prevent damage to the equipment (load and floating support) it is necessary to provide damping means between them.
However, during transport, and before the load is transferred there is a contrary requirement for a rigid, non-resilient link between them without any damping means which link is usually an iron-to-iron link. Damping units therefore tend to be brought into use only just before unloading. One known technique consists in lifting the load on the floating support so as to be able to insert damping units between said floating support and the load. However, there are disadvantages to this solution.
Even if unloading takes place immediately after the damping units are in place, there remains a period during which the load is resiliently connected to a floating support and therefore there is a danger of resonance under the effect of the swell. Further, if the lifting operation for inserting the damping units is to avoid the original problem which the damping units are supposed to solve, it is necessary for the lifting equipment to form part of the floating support itself. This requires large hoisting means and extra support points, etc.